Hey Nick,
I pushed the recent HS proposals to my torspec git repo.
You can find them on branch 'hs_experimentation' at https://git.torproject.org/user/asn/torspec.git .
My next step would be to write the anti-enumeration crypto part of xxx-hs-id-keys-and-onion-leaking.txt (as I started doing with c8b7e40).
Feel free to work on them. Maybe send me an IRC message before you start touching them so that we don't do change the same areas of the spec.